There has been conventionally employed a vehicle having tires or crawlers attached to the lower part thereof for contacting a road or the ground whereby a chassis of the vehicle is movable freely on the road or ground. The prior art vehicle of this type has such a structure that the driving force is generated by turning the tires or the crawlers and the tires are turned in a different direction by a steering wheel or the crawlers are turned in a different direction by generating different revolutions in both crawlers. Such a propelled vehicle has an object to travel fast if it travels straight or carries a load from one point to another point. To achieve the object, the prior art vehicle has a structure intended only to facilitate operability in the traveling direction. This is caused by the fact that the prior art vehicle emphasizes straight traveling on a highway or public road and is manufactured to meet this intention.
However, there is a case where the vehicle travels not only straight, but also moves in a lateral direction perpendicular to the normal traveling direction. For example, there is a case where the vehicle loaded with a construction machine or building machine is forced to approach a wall surface of a house or building at the side surface of the vehicle and thereafter the vehicle is moved laterally relative to the wall surface. Especially, in a working machine having a vertically movable platform on which an operator works at an elevated spot (hereinafter referred to simply as a working machine), the working machine approaches the side of the building at a side surface thereof and the platform approaches the wall surface of the building, which results in improving working efficiently. That is, if the platform can be approached close to the wall surface, as by the vehicle being moved laterally until the operator's hand can touch the wall surface, this thereby facilitates painting on the wall surface or laying boards on the wall surface.
The prior art vehicle can cope with such a case by steering the front wheels while moving the vehicle to the front and rear so as to approach the wall surface, namely, by pulling the vehicle over to the side of the wall surface, which is however troublesome in operation and is not performed when there is no space to move the vehicle to the front and rear.
Accordingly, there is a desire to provide a vehicle capable of moving laterally at right angles relative to the normal traveling direction. To achieve this object, there is known a vehicle capable of turning the wheels supporting the vehicle chassis in the horizontal direction so that all the wheels can move at right angles relative to the traveling direction, whereby the vehicle can move laterally. There is another known vehicle which can move laterally by a special push car which is accommodated in the lower portion of the vehicle. However, such a prior art vehicle becomes heavy at the lower portion thereof and the structure becomes complex, whereby such a vehicle has not been commonly used. To meet the need, there is thus desired a mechanism with a simple structure and capable of moving laterally relative to the traveling direction.